To meet the climate commitments we’ve made to the world, both townies and farmers will have to play their roles, and support each other. To fail would damage our reputation and economy. Photo: Lynn Grieveson

Rod Oram: the crucial but contentious methane decision

In his latest column on New Zealand's transition to a low carbon economy, Rod Oram looks at why there is such intense lobbying and debate over how to handle methane emissions.

We’ll know by Christmas the salient features of the most important new legislative framework this country will adopt in generations, the Government promises.

Meanwhile, intense lobbying is underway to shape one of the most critical components of it which will significantly determine the legislation’s effectiveness.

The framework is the Zero Carbon Bill, which will set our long-term climate goals – the Government is likely to propose net zero emissions of human-induced greenhouse gases by 2050 – and the mechanisms to guide our policy, technical, economic, political and social responses to achieve that formidable challenge.

At the heart of the methane issue are some still evolving scientific answers to questions about methane’s warming potential and how countries should best handle its reduction.

The crucial component is how to handle methane. Globally, the gas contributes 28 percent of human-induced climate warming. But it’s a far more intense issue for us. Almost half our greenhouse gas emissions are generated by our agriculture. Of those, 10.3 percent are from nitrous oxide, a long-lived and very potent climate changer, and 35.5 percent from methane, a short-lived but also very powerful climate force. Of that farm methane, 68 percent comes from ruminant animals, overwhelmingly in the dairy and red meat sectors.

When, how and by how much we reduce methane will have far ranging impacts on climate and the economy. Simplistically, if we make good decisions, we’ll meet our climate goals, and our agricultural scientists and farmers will contribute to the global challenge of making meat and dairy foods more climate compatible. If we do it badly, we’ll damage our climate and farming reputations, and thus our economy.

None of this is easy. At the heart of the methane issue are some still evolving scientific answers to questions about methane’s warming potential and how countries should best handle its reduction.

The debate intensified here in June with the publication of a paper in Climate and Atmospheric Science, a new addition to Nature’s stable of science journals.

Two of the authors were Prof. David Frame, a climate scientist at Victoria University and director of its New Zealand Climate Change Research Institute, and Adrian Macey, a retired diplomat who was NZ’s first Climate Change Ambassador 2006-10, then chair of the UN’s Kyoto climate protocol until 2011. His current roles include an adjunct professorship at the Institute.

Frame, Macey and their colleagues argued that the conventional way of measuring methane’s climate impact was flawed, and that they had devised a better way. Using this new metric, they argued that because methane was short-lived, so was its impact on climate change. Therefore if we stabilised our methane emissions at or slightly below current levels they would contribute no additional warming.

Thus, any policy pressure to reduce methane emissions more steeply should wait until there were proven, cost-effective technologies for farmers to do so. Delaying reductions would not change the methane’s climate impact.

This has encouraged some organisations in the primary sector to renew their calls for agriculture to be excluded from our over-arching climate framework to guide our transition to a low emissions economy, or at least to give agriculture an easy ride in it.

Fonterra’s goal for example is to have its supplying farms generate no more methane emissions in 2030 than they do now. To the extent its farmers can reduce emissions, Fonterra’s hopes that will enable them to increase milk production.

But the science at the centre of this comes with some variation in experts’ judgements. Frame and colleagues are using science that is well known, and their new metric is a variation on the existing one used in the Paris Agreement on climate. However, while the UN’s climate body does adjust the factor it uses to equate the climate impact of methane with the impact of carbon dioxide as the science improves, it has yet to change the underlying methodology.

Methane has a much faster, bigger impact on climate change in its first few years after emission than does carbon dioxide. By about 12 years, about one-third of the methane has broken down, reducing the climate impact of the gas. By 20 years or so little of the gas remains, leading Frame and colleagues to argue that its climate impact is negligible.

Thus, if farmers keep emissions static, as they have over the past decade or so, or reduce them slightly as their farming efficiency continues, then the steady flow of methane is not contributing to additional climate change, Frame and colleagues argue. In contrast, carbon dioxide is very long-lived so its emissions add to the atmospheric stock and thus exacerbate warming, which no climate scientists dispute.

However, scientific views differ on methane’s long-tail effect on climate.

“A constant flow of methane emissions results in a constant methane concentration after around 50 years, but its impact on temperature continues to increase for several centuries. Three hundred years after a constant flow of methane emission has started, the warming effect is more than twice as high as it is after 50 years,” notes a report in August by Simon Upton, the Parliamentary Commissioner for the Environment.

“If New Zealand’s emissions of livestock methane were held steady at 2016 levels, then within about ten years the amount of methane in the atmosphere from that source would level off. However, the warming effect of that methane would continue to increase, at a gradually declining rate, for more than a century. In the year 2050, holding New Zealand’s livestock methane steady at 2016 levels would cause additional warming of 10-20 percent above current levels. This warming would increase to 25-40 percent by 2100.”

Moreover, Frame and colleagues argue that the current UN measure for methane overestimates its impact on climate change. Yet there are other equally respected scientists who argue the opposite, as Wise Response, an NZ climate change lobby group led by scientists, noted in their submission to the government on the Zero Carbon Bill.

The scientists they cite believe the UN’s current methane measure “underestimates the amount of CO2 reduction needed to offset the warming effects of a given emission of methane by a factor of 2.5, and also underestimates the benefits of rapid reductions of methane emissions.” Thus, there are strong arguments for a sharp, rapid cut in methane to help slow down the rise in temperatures while utmost efforts are also made to aggressively cut CO2.

While the science is fundamentally important and will continue to clarify the role of methane and the world’s response to it, there are additional reasons for New Zealand to be reducing methane emissions faster and sooner than Frame, Macey and colleagues argue.

First, many countries look to us as agricultural innovators, such as the UK in particular, as this column notedtwo weeks ago. They are expecting us to be a leader on the science of reducing ruminant animals’ emissions, and the farming practices to do so economically.

Second, a big transformation of the global food system is underway, as I described in this column in August. Competition is coming from low emissions foods. It’s better for us to be a leader in low emissions meat and dairy than not. The best ways to drive such innovation is by climate policies that incentivise emission reductions and science and R&D policies that support that.

... if National doesn’t get its climate act together very soon, the Government should take an alternative approach: declare by Christmas what the Bill will include.

Third, to meet the Paris climate commitments we’ve made to the world, both townies and cockies, to over-simplify a monumental challenge, will have to play their roles, and encourage and support each other in doing so.

If farmers reduce methane and nitrous oxide but people in towns stick with petrol and diesel guzzling cars we will fail. If townies electrify the car fleet, switch heavy transport to hydrogen and industrial processes to electricity but farmers don’t reduce methane, we’ll fail.

Either fail would greatly damage our reputation and economy.

Some options for the best mechanisms to achieve these complex goals, including reducing methane, are explored at length in the Productivity Commission’s final report on our transition to a low-emissions economy.

This methane debate, though, was already complicated enough before National injected an unwelcome political dimension over the past 10 days. Its self-inflicted damage over Jami-Lee Ross’ character and actions, Bridge’s leadership style and the party’s fund-raising is taking its energy and focus away from many crucial political tasks. A key one is agreeing with the Labour-led coalition on the salient points of the Zero Carbon Bill. Such long lasting, far-reaching legislation must have all-party support.

However, if National doesn’t get its climate act together very soon, the Government should take an alternative approach: declare by Christmas what the Bill will include. Then work on getting National on board during the drafting process so parliament can debate and pass the Bill by the middle of next year.

Above all, the most important step the Government and all other parties must take is simple: define our 2050 climate target in the Bill and the mechanisms to drive it such as an independent Climate Change Commission.

Then leave the Commission to set five-year, sinking carbon budgets, which will adapt over time to the changing science, technology and economics driving emissions reductions; and to evaluate the success of successive governments’ policies in doing so.

The Commission, with its independence and long-term remit, is the place for settling arguments such as this one over methane. It is a seriously bad idea to let the Government or opposition parties of the day to succumb to narrow, short term political interests by making such decisions themselves.

This is the latest in a series of Rod Oram’s columns examining key sectors in the Productivity Commission’s final report on New Zealand’s transition to a low-emissions economy.

Future columns will examine, for example, transport, innovation and socially just transitions.

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